Silverlining - so sorry you are going through this.
At my 20 week scan there was much talk of soft markers for other potentially fatal / non-viable syndromes (not Edwardes AFAIK), and based on that, I did have amnio, with a thankfully re-assuring result.
What I came through that situation thinking was that if I was doing it all again, I would have CVS, not wait until later. The emotional impact of a more advanced pregnancy, a baby you have felt moving, is, I feel, a strong one.
And I think it's more complex than 'would you abort', too. I found it hugely helpful to know in advance that my baby would have physical differences. I was able to do research, find the relevant support group, and do all the thinking I had to do. By the time my baby was born, the fact that he had bones missing had become 'ordinary' in my mind, and all I had to do was love him and get to know him. Much better than having his condition announced in a packed unprivate post-natal ward by the insensitive brute of a peadiatrician that was on duty!
In our case, the possibilities were Down's and two other trisomies - both of which were fatal / non-viable. Our personal decision would have been to terminated for the non-viable trisomies, but certainly not for Down's or DS's physical difference.
Silverlining - I do know that even the slightest statistical risk feels like a total emotional one - and I really feel for you.